Majungasaurus
Majungasaurus ''was an abelisaurid dinosaur from the Late Cretaceous that lived in the island of Madagascar from 70 to 66 million years ago, at the end of the Cretaceous Period. The genus contains a single species, ''Majungasaurus crenatissimus. This dinosaur was briefly called Majungatholus, a name which is now considered a junior synonym of Majungasaurus. Physical Description Majungasaurus was a medium-sized theropod that typically measured 6–7 meters (20–23 ft) in length, including its tail. Fragmentary remains of larger individuals indicate that some adults reached lengths of more than 8 meters (26 ft). Sampson and Witmer estimated an average weight for an adult Majungasaurus of 1,100 kilograms (2,400 lb). The specimen they based it on (FMNH PR 2100) was not the largest one discovered. Larger specimens of Majungasaurus crenatissimus could have been similar in size to its relative''Carnotaurus'', which has been estimated to weigh 1,500 kilograms (3,300 lb). The skull of Majungasaurus is exceptionally well-known compared to most theropods and generally similar to that of other abelisaurids. Like other abelisaurid skulls, its length was proportionally short for its height, although not as short as in Carnotaurus. The skulls of large individuals measured 60–70 centimeters (24–28 in) long. The tall premaxilla (frontmost upper jaw bone), which made the tip of the snout very blunt, was also typical of the family. However, the skull of Majungasaurus was markedly wider than in other abelisaurids. All abelisaurids had a rough, sculptured texture on the outside faces of the skull bones, and Majungasaurus was no exception. This was carried to an extreme on the nasal bones of Majungasaurus, which were extremely thick and fused together, with a low central ridge running along the half of the bone closest to the nostrils. A distinctive dome-like horn protruded from the fused frontal bones on top of the skull as well. In life, these structures would have been covered with some sort of integument, possibly made of keratin. Computed tomography (CT scanning) of the skull shows that both the nasal structure and the frontal horn contained hollow sinus cavities, perhaps to reduce weight. The teeth were typical of abelisaurids in having short crowns, although Majungasaurus bore seventeen teeth in both the maxilla of the upper jaw and the dentary of the lower jaw, more than in any other abelisaurid except Rugops. Life restoration The postcranial skeleton of Majungasaurus closely resembles those of Carnotaurus and Aucasaurus, the only other abelisaurid genera for which complete skeletal material is known. Majungasaurus was bipedal, with a long tail to balance out the head and torso, putting the center of gravity over the hips. Although the cervical (neck) vertebrae had numerous cavities and excavations (pleurocoels) to reduce their weight, they were robust, with exaggerated muscleattachment sites and ribs that interlocked for strength. Ossified tendons attached to the cervical ribs, giving them a forked appearance, as seen in Carnotaurus. All of these features resulted in a very strong and muscular neck. Uniquely, the cervical ribs of Majungasaurus had long depressions along the sides for weight reduction.5 The humerus (upper arm bone) was short and curved, closely resembling those of Aucasaurus and Carnotaurus. Also like related dinosaurs, Majungasaurus had very short forelimbs with four extremely reduced digits, first reported with only two very short external fingers and no claws. The hand and finger bones of Majungasaurus, like other majungasaurines, lacked the characteristic pits and grooves where claws and tendons would normally attach, and its finger bones were fused together, indicating that the hand was immobile. In 2012, a better specimen was described, showing that the lower arm was robust, though short, and that the hand contained four metatarsals and four, probably inflexible and very reduced, fingers, with small claws on the second and third finger. The phalanx formula was 1-2-2-1-0. Like other abelisaurids, the hindlimbs were stocky and short compared to body length. The tibia (lower leg bone) of Majungasaurus was even stockier than that of its relative Carnotaurus, with a prominent crest on the knee. Theastragalus and calcaneum (ankle bones) were fused together, and the feet bore three functional digits, with a smaller first digit that did not contact the ground. Paleobiology Skull ornamentation Majungasaurus is perhaps most distinctive for its skull ornamentation, including the swollen and fused nasals and the frontal horn. Other ceratosaurs, including Carnotaurus, Rajasaurus, and Ceratosaurus itself bore crests on the head. These structures are likely to have played a role in intraspecific competition, although their exact function within that context is unknown. The hollow cavity inside the frontal horn of Majungasaurus would have weakened the structure and probably precluded its use in direct physical combat, although the horn may have served a display purpose. While there is variation in the ornamentation of Majungasaurus individuals, there is no evidence for sexual dimorphism. Carcharodontosaurus teeth skull head Egypt Feeding Scientists have suggested that the unique skull shape of Majungasaurus and other abelisaurids indicate different predatory habits than other theropods. Whereas most theropods were characterized by long, low skulls of narrow width, abelisaurid skulls were taller and wider, and often shorter in length as well. The narrow skulls of other theropods were well equipped to withstand the vertical stress of a powerful bite, but not as good at withstanding torsion (twisting). In comparison to modern mammalian predators, most theropods may have used a strategy similar in some ways to that of long- and narrow-snouted canids, with the delivery of many bites weakening the prey animal. Majungasaurus was the largest predator in its environment, while the only known large herbivores at the time were sauropods like Rapetosaurus. Scientists have suggested that''Majungasaurus'', and perhaps other abelisaurids, specialized on hunting sauropods. Adaptations to strengthen the head and neck for a bite-and-hold type of attack might have been very useful against sauropods, which would have been tremendously powerful animals. This hypothesis may also be supported by the hindlegs of Majungasaurus, which were short and stocky, as opposed to the longer and more slender legs of most other theropods. While Majungasaurus would not have moved as fast as other similar-sized theropods, it would have had no trouble keeping up with slow-moving sauropods. The robust hindlimb bones suggest very powerful legs, and their shorter length would have lowered the animal's center of gravity. Thus Majungasaurus may have sacrificed speed for power. Majungasaurus tooth marks on Rapetosaurus bones confirm that it at least fed on these sauropods, whether or not it actually killed them. Cannibalism Although sauropods may have been the prey of choice for Majungasaurus, discoveries published in 2007 detail finds in Madagascar that indicate the presence of other Majungasaurus in their diet. Numerous bones of''Majungasaurus'' have been discovered bearing tooth marks identical to those found on sauropod bones from the same localities. These marks have the same spacing as teeth in Majungasaurus jaws, are of the same size as''Majungasaurus'' teeth, and contain smaller notches consistent with the serrations on those teeth. As Majungasaurus is the only large theropod known from the area, the simplest explanation is that it was feeding on other members of its own species. Suggestions that the Triassic Coelophysis was a cannibal have been recently disproven, leaving Majungasaurus as the only non-avian theropod with confirmed cannibalistic tendencies, although there is some evidence that cannibalism may have occurred in other species as well. It is unknown if Majungasaurus actively hunted their own kind or only scavenged their carcasses. However, some researchers have noted that modern Komodo monitors sometimes kill each other when competing for access to carcasses. The lizards will then proceed to cannibalize the remains of their rivals, which may suggest similar behavior in Majungasaurus and other theropods. In Dinosaur Revolution It appeared in the third episode where a Rahonavis heard the steps of an approaching Majungasaurus as it almost stepped on it but the quick little raptor managed to escape. As the Majungasaurus attacked a Rapetosaurus the Rahonavis saw the battle and it's babies came and saw the Rahonavis and chased it into a tree, but later were eaten by giant Beelzebufo frogs. At the end the female Majungasaurus has killed one Rapetosaurus and ate it. Appearence It was a medium sized carnivore that was smaller than T. rex ''but bigger than ''Velociraptor. With a short snout and small arms and weighed about 1.5 tonnes. The Majungasaurus' color is based on an African Wild Dog. Category:Dinosaurs Category:Main Antagonist Category:Animals from Madagascar Category:Cretaceous animals Category:Theropods Category:Carnivores Category:Vertebrates Category:Animals from Africa Category:Apex predators Category:Intelligent dinosaurs Category:Survival Tactics animals Category:Ceratosaurs Category:Abelisauridae